Mild hypothermia promotes the viability of in vitro-produced bovine blastocysts and their transcriptional expression of the cold-inducible transcription factor Rbm3 during in vitro culture

Carnosine supplementation in cryopreservation solution improved frozen-thawed bovine embryo viability

Cryopreservation adversely affects embryo quality and viability in vitro. We investigated the effects of cryopreservation solutions supplemented with the antioxidant carnosine on frozen-thawed bovine embryo viability. Bovine blastocysts were produced in vitro and cryopreserved using slow freezing. The rates of re-expanded and hatched blastocysts in the 50 μg/ml carnosine-supplemented group at 4, 24, and 48 h after thawing were higher than those in the control (P < 0.05) group. In frozen-thawed embryos, cryopreservation solution supplemented with carnosine (50 μg/ml) significantly reduced reactive oxygen species (ROS) production (P < 0.05), decreased TUNEL-positive apoptotic cells (P < 0.05), and increased the mRNA expression of BCL2 (P < 0.05), an apoptosis suppressor gene. The expression of translocase of outer mitochondrial membrane 20 (TOMM20), which is involved in protein mitochondrial transport, in the carnosine (50 μg/ml)-treated embryos was significantly higher than that in the control group (P < 0.05). ATP production in frozen-thawed embryos in the 50 μg/ml carnosine-supplemented group was significantly higher than that in the control group (P < 0.05), however no significant difference in the total number of cells per embryo among the groups was observed. These results suggest that supplementing the cryopreservation solution with carnosine can improve the viability of frozen-thawed bovine embryos by reducing oxidative damage.

The transcription factor RUNX1 affects the maturation of porcine oocytes via the BMP15/TGF-β signaling pathway

Bone morphogenetic protein 15 (BMP15) is specifically expressed in oocytes in pigs at all stages from early stages to ovulation and has an important role in oocyte maturation. However, there are few reports on the molecular mechanisms by which BMP15 affects oocyte maturation. In this study, we identified the core promoter region of BMP15 using a dual luciferase activity assay and successfully predicted the DNA binding motif of the transcription factor RUNX1. The effect of BMP15 and RUNX1 on oocyte maturation was examined using the first polar body extrusion rate, a reactive oxygen species (ROS) assay and total glutathione (GSH) content at three time points of 12, 24 and 48 h of in vitro culture of porcine isolated oocytes. Subsequently, the effect of the transcription factor RUNX1 on the TGF-β signaling pathway (BMPR1B and ALK5) was further verified using RT-qPCR and Western blotting. We found that the overexpression of BMP15 significantly increased the first polar body extrusion rate (P < 0.01) and total glutathione content of oocytes cultured in vitro for 24 h and decreased reactive oxygen levels (P < 0.01), whereas interference with BMP15 decreased the first polar body extrusion rate (P < 0.01), increased reactive oxygen levels in oocytes cultured in vitro for 24 h (P < 0.01), and decreased glutathione content (P < 0.01). The dual luciferase activity assay and online software prediction showed that RUNX1 is a potential transcription factor binding to the core promoter region (-1203/-1423 bp) of BMP15. Overexpression of RUNX1 significantly increased the expression of BMP15 and oocyte maturation rate, while inhibition of RUNX1 decreased the expression of BMP15 and the oocyte maturation rate. Moreover, the expression of BMPR1B and ALK5 in the TGF-β signaling pathway increased significantly after overexpression of RUNX1, whereas their expression decreased after inhibition of RUNX1. Overall, our results suggest that the transcription factor RUNX1 positively regulates the expression of BMP15 and influences oocyte maturation through the TGF-β signaling pathway. This study provides a theoretical basis for further complementing the BMP15/TGF-β signaling pathway to regulate mammalian oocyte maturation.

RBM3 is an outstanding cold shock protein with multiple physiological functions beyond hypothermia

RNA-binding motif protein 3 (RBM3), an outstanding cold shock protein, is rapidly upregulated to ensure homeostasis and survival in a cold environment, which is an important physiological mechanism in response to cold stress. Meanwhile, RBM3 has multiple physiological functions and participates in the regulation of various cellular physiological processes, such as antiapoptosis, circadian rhythm, cell cycle, reproduction, and tumogenesis. The structure, conservation, and tissue distribution of RBM3 in human are demonstrated in this review. Herein, the multiple physiological functions of RBM3 were summarized based on recent research advances. Meanwhile, the cytoprotective mechanism of RBM3 during stress under various adverse conditions and its regulation of transcription were discussed. In addition, the neuroprotection of RBM3 and its oncogenic role and controversy in various cancers were investigated in our review.